Neutron Holography

The idea of holographic imaging was conceived by Dennis Gabor already in 1948. Due to technical reasons, however, practical applications could be realized only decades later after the development of laser technology. Today, the striking features of threedimensional holograms offering views from different perspectives are well known to the general public. The recording of holograms is not restricted to visible light but, in principle, can be performed using any kind of waves and, indeed, both electromagnetic and matter waves are of considerable interest in this context. Following theoretical analysis the first production of holograms which, according to the original concept of Gabor, were based on the wave properties of electrons was successful in 1990. In 1996 the first X-ray holograms could be produced. The use of electrons or X-rays renders it possible to visualize the arrangement of single atoms within their neighbourhood in a three-dimensional way thus providing a gain in resolution of several orders of magnitude over holograms obtained with visible light. Holography based on electrons suffers from strong distortions and applications are restricted to the imaging of surfaces. X-rays penetrate more deeply in condensed matter than electrons but are not well suited for imaging very light atoms like hydrogen and combinations of atoms belonging to elements of very distant atomic numbers. Neutrons are not subject to these restrictions. Another strong point arises from the fact that electrons and X-rays interact with the atomic shell while neutrons primarily interact with the atomic nuclei thus providing direct access to their positions and entailing a further improvement in resolution of several orders of magnitude. In 2001, for the first time, Hungarian physicists together with the applicant proposed techniques for the recording of neutron holograms which could be confirmed in experiments independently both by this group and Canadian scientists. The goals of the present project are twofold: First, various technical problems of neutron holography are to be studied and, among others, it shall be shown that recording times can be reduced from presently 10 days to about 1 hour. Second, using carefully selected examples it shall be demonstrated in which fields future applications of neutron holography may typically arise. Among those there are substances containing substantial amounts of hydrogen (hydrogen storage materials, organic substances, minerals of geological importance) as well as novel magnetic materials and intermetallic compounds.

The idea of holographic imaging was conceived by Dennis Gabor already in 1948. Due to technical reasons, however, practical applications could be realized only decades later after the development of laser technology. Today, the striking features of threedimensional holograms offering views from different perspectives are well known to the general public. The recording of holograms is not restricted to visible light but, in principle, can be performed using any kind of waves and, indeed, both electromagnetic and matter waves are of considerable interest in this context. Following theoretical analysis the first production of holograms which, according to the original concept of Gabor, were based on the wave properties of electrons was successful in 1990. In 1996 the first X-ray holograms could be produced. The use of electrons or X-rays renders it possible to visualize the arrangement of single atoms within their neighbourhood in a three-dimensional way thus providing a gain in resolution of several orders of magnitude over holograms obtained with visible light. Holography based on electrons suffers from strong distortions and applications are restricted to the imaging of surfaces. X-rays penetrate more deeply in condensed matter than electrons but are not well suited for imaging very light atoms like hydrogen and combinations of atoms belonging to elements of very distant atomic numbers. Neutrons are not subject to these restrictions. Another strong point arises from the fact that electrons and X-rays interact with the atomic shell while neutrons primarily interact with the atomic nuclei thus providing direct access to their positions and entailing a further improvement in resolution of several orders of magnitude. In 2001, for the first time, Hungarian physicists together with the applicant proposed techniques for the recording of neutron holograms which could be confirmed in experiments independently both by this group and Canadian scientists. The goals of the present project are twofold: First, various technical problems of neutron holography are to be studied and, among others, it shall be shown that recording times can be reduced from presently 10 days to about 1 hour. Second, using carefully selected examples it shall be demonstrated in which fields future applications of neutron holography may typically arise. Among those there are substances containing substantial amounts of hydrogen (hydrogen storage materials, organic substances, minerals of geological importance) as well as novel magnetic materials and intermetallic compounds.